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memory: Share FlatView's and dispatch trees between address spaces

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This allows sharing flat views between address spaces (AS) when
the same root memory region is used when creating a new address space.
This is done by walking through all ASes and caching one FlatView per
a physical root MR (i.e. not aliased).

This removes search for duplicates from address_space_init_shareable() as
FlatViews are shared elsewhere and keeping as::ref_count correct seems
an unnecessary and useless complication.

This should cause no change and memory use or boot time yet.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-13-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alexey Kardashevskiy 2017-09-21 18:51:04 +10:00 committed by Paolo Bonzini
parent 0221848764
commit 967dc9b119
1 changed files with 45 additions and 11 deletions
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56
memory.c
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@ -47,6 +47,8 @@ static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners
static QTAILQ_HEAD(, AddressSpace) address_spaces
= QTAILQ_HEAD_INITIALIZER(address_spaces);
static GHashTable *flat_views;
typedef struct AddrRange AddrRange;
/*
@ -761,6 +763,7 @@ static FlatView *generate_memory_topology(MemoryRegion *mr)
flatview_add_to_dispatch(view, &mrs);
}
address_space_dispatch_compact(view->dispatch);
g_hash_table_replace(flat_views, mr, view);
return view;
}
@ -930,11 +933,47 @@ static void address_space_update_topology_pass(AddressSpace *as,
}
}
static void address_space_update_topology(AddressSpace *as)
static void flatviews_init(void)
{
if (flat_views) {
return;
}
flat_views = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,
(GDestroyNotify) flatview_unref);
}
static void flatviews_reset(void)
{
AddressSpace *as;
if (flat_views) {
g_hash_table_unref(flat_views);
flat_views = NULL;
}
flatviews_init();
/* Render unique FVs */
QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
if (g_hash_table_lookup(flat_views, physmr)) {
continue;
}
generate_memory_topology(physmr);
}
}
static void address_space_set_flatview(AddressSpace *as)
{
FlatView *old_view = address_space_get_flatview(as);
MemoryRegion *physmr = memory_region_get_flatview_root(old_view->root);
FlatView *new_view = generate_memory_topology(physmr);
MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
FlatView *new_view = g_hash_table_lookup(flat_views, physmr);
assert(new_view);
flatview_ref(new_view);
if (!QTAILQ_EMPTY(&as->listeners)) {
address_space_update_topology_pass(as, old_view, new_view, false);
@ -970,10 +1009,12 @@ void memory_region_transaction_commit(void)
--memory_region_transaction_depth;
if (!memory_region_transaction_depth) {
if (memory_region_update_pending) {
flatviews_reset();
MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);
QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
address_space_update_topology(as);
address_space_set_flatview(as);
address_space_update_ioeventfds(as);
}
memory_region_update_pending = false;
@ -2696,13 +2737,6 @@ AddressSpace *address_space_init_shareable(MemoryRegion *root, const char *name)
{
AddressSpace *as;
QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
if (root == as->root && as->malloced) {
as->ref_count++;
return as;
}
}
as = g_malloc0(sizeof *as);
address_space_init(as, root, name);
as->malloced = true;